1. Field of the Invention
The present invention refers to humid compressed-gas dryers.
2. Description of the Related Art
Compressed-gas dryers are usually employed to remove moisture from a flow of compressed gas or air.
The moisture content in a compressed gas is generally known as being the main cause of corrosion and premature breakdown of piping systems, leading eventually to a malfunction or even full unserviceableness of the machines that use such compressed gas. Therefore, in all systems that make use of compressed gas, the need arises for the moisture content thereof to be eliminated or reduced to as low a value as possible prior to such gas being supplied to the operating machines.
Dryers for humid compressed gases reduce the water content in the compressed gas by cooling the gas, for example by making use of a refrigerating circuit. The water vapor in the cooled compressed gas converts by condensation into liquid droplets that are separated from the gas with the aid of a condensate separator, which performs by removing the droplets from the flow of gas.
Known in the art are dryers for humid compressed gases that comprise a plate-type heat-exchanger formed of a stack of plates that are attached to each other by brazing along a peripheral edge thereof and have a plurality of mutually aligned apertures, which define fluid conduits that extend throughout the stack of plates to guide both the compressed gas and a refrigerant medium inside the heat-exchanger. Adjacent plates in the stack define fluid conduits therebetween, which enable a heat exchange process to take place between the compressed gas and the refrigerant medium.
The need is generally and widely felt in the art for extremely compact and small-sized compressed-gas dryers to be provided, which additionally feature adequate mechanical strength to withstand the pressure conditions which they are subject to, and are effective in ensuring an efficient heat-exchange effect between the compressed gas and the refrigerant medium flowing therethrough.
Usually, the heat-exchangers of such compressed-gas dryers are made of plates of stainless steel, or other equivalent metal alloys. On the inner surfaces of the plates, i.e., the surfaces that define the above-cited channels, there is formed a relief, i.e., projecting profile, which is aimed at increasing the turbulent flow of the fluids, so as to correspondingly increase the heat-exchange efficiency.
Generally, the pressure strength, i.e., bursting strength, must be sufficient to ensure a safety coefficient that is at least equal to five times the operating pressure. For example, at an operating pressure of 16 bar, the bursting strength should be higher than 80 bar.
It can be most readily appreciated that, where high operating pressures are used, the need arises for heat-exchangers to be employed that make use of plates of a correspondingly increased thickness, thereby causing the overall dimensions of the dryers to be increased accordingly.
The provision of a pressure-resistant condensate separator, along with the channels adapted to convey the compressed gas from the heat-exchanger to the same condensate separator, contributes to a further increase in the overall size, as well as the complexity of the dryer.